This is taking retail marketing to a whole new level, watching consumers as they buy, then the interpretation of their body language.  I guess that this could be added in as another factor for the Taguchi method or multivariate testing.  Think about the amount of communication the body gives off and the amount of data that can be captured and manipulated if in the right hands.

Why do consumers buy the same brand of coffee and mayonnaise over and over again, but will often purchase different brands of cold cereal and chocolates? It’s hardly happenstance, according to a new study by The Nielsen Company. Nielsen’s study of shopper behavior shows that consumers present distinct shopping modes at the supermarket that dictate what ends up in their grocery bags.

 

http://us.acnielsen.com/news/20070815.shtml